1. Field of the Invention
This invention relates to substantially anhydrous complexes of polyvinylpyrrolidone (PVP) and hydrogen peroxide (H.sub.2 O.sub.2), and to a process for preparing such stabilized complexes as free-flowing, uniform, fine white powders containing a predetermined amount of H.sub.2 O.sub.2 therein.
2. Description of the Prior Art
Stabilized H.sub.2 O.sub.2 compositions have found wide utility in commercial and industrial applications, e.g. as disinfectants, sterilization agents, as bleaching materials, washing concentrates, etchants, in cosmetic preparations, as clarification agents for alcoholic and fermented beverages, and as a catalyst in polymerizations requiring a free radical source. In biological applications which require a disinfectant or sterilization agent, such H.sub.2 O.sub.2 compositions require release of an effective amount of oxygen at a controlled rate without storage decomposition caused by interaction with organic matter, light and/or heat.
Shiraeff, in U.S. Pat. Nos. 3,376,110 and 3,480,557, discloses a solid, stabilized hydrogen peroxide composition of hydrogen peroxide and a polymeric N-vinyl heterocyclic compound prepared in an aqueous solution of the components. These compositions generally were prepared by mixing various weights of PVP and aqueous H.sub.2 O.sub.2, and evaporating the solution to dryness. The Shiraeff composition, which was believed to be a solid, dry complex, was described as not necessarily anhydrous due to the hydrophilic nature of the PVP and the water present in the reaction solution. Shiraeff further stated that such amounts of water could be tolerated, however, if it did not affect the solid dry characteristics of the complexes. The H.sub.2 O.sub.2 content of the composition was given as being at least 2%, and preferably 4.5 to 70% by weight. Prolonged drying to remove water from such compositions, however, resulted in loss of H.sub.2 O.sub.2 forming a brittle, transparent, gummy, amorphous product. In U.S. Pat. No. 3,480,557, the aqueous PVP-H.sub.2 O.sub.2 complexes, upon heating to dryness, produced hard, brittle chips which had a variable H.sub.2 O.sub.2 content ranging from about 3.20 to 18.07% by weight, depending upon the drying times.
Drauz et al., in U.S. Pat. No. 4,564,514, disclosed a process for making water-free organic hydrogen peroxide solutions from aqueous solutions of hydrogen peroxide. The Drauz process effected removal of water by azeotropic distillation of water in high boiling organic solvents.
Accordingly, it is an object of this invention to provide substantially anhydrous complexes of PVP and H.sub.2 O.sub.2.
Another object herein is to provide such anhydrous complexes of PVP and H.sub.2 O.sub.2 in predetermined molar ratios of PVP to H.sub.2 O.sub.2.
A particular object of the present invention is to provide stable, anhydrous complexes of PVP and H.sub.2 O.sub.2 in a molar ratio of between about 2:1 and 1:1, respectively.
A further object of the invention is to provide a process of precipitating anhydrous complexes of PVP and H.sub.2 O.sub.2 from an anhydrous organic solvent as a substantially uniform, free-flowing, fine white powder.
Still another object therein is to provide an anhydrous process of making a stabilized anhydrous PVP-H.sub.2 O.sub.2 complex containing about 23% H.sub.2 O.sub.2.
These and other objects and features of the invention will be made apparent from the following description.